Our study aimed to analyze the risk factors associated with the occurrence and severity of pneumococcal infection (PI) in systemic lupus erythematosus (SLE) patients.

Medical records of all SLE patients admitted in our department from January 2005 to December 2014 were retrospectively reviewed. SLE patients were separated in 2 groups according to whether they had PI or not. Medical records of all consecutive patients (with and without SLE) admitted in our department for PI over the same period of time were also reviewed. Clinical characteristics associated with PI occurrence and severity were analyzed in SLE patients.

One hundred and ninety SLE patients (42.2+14.9 years; 87.4% females) were hospitalized over a 10-year period. PI was the reason for admission in 6 (3.2%) patients, including 5 cases of invasive infection. With a follow-up of 2112.8 patient-years for the total cohort, incidence of invasive PI in SLE was of 236/100,000 patient-years. PI occurred at a younger age (43.5+14.9 versus 65.3+18.7 years, P<0.01) and were more severe, with a higher frequency of invasive infection (P<0.001) and higher need for ICU admission (P<0.05) in SLE as compared to non SLE patients. Risk factors associated with PI in SLE patients were a serum gammaglobulin level<5g/L (P<0.01) and a past history of lupus nephritis (P<0.05), only. Steroids (P<0.001) and immunosuppressive drugs (P<0.05) were associated with infection severity.

SLE is a disease of high susceptibility for invasive pneumococcal infections. Our study points to the need for vaccination against Streptococcus pneumoniae in SLE.